Python 11th day

Start learning the second module:

Adorner:

Describe:

Adorner principle:

1. Cannot modify the source code of the decorated function

2, can not modify the decoration of the function of the caller test

To implement the adorner:

Higher order function + nested function = Adorner

Higher order functions:

Type I: a function that functions as an argument, which can be called a higher order function

　　　　　　　　

 1  def  fun_1 (fun_2): #  fun_1 is a higher order function  2  Span style= "COLOR: #0000ff" >print  ( " 1   " )  3   fun_2 ()  4  5  def   Fun_2 ():  6  print  ( 2   " )  7  8  fun_1 (fun_2) 

Type II: The function that contains the function name in the return value, also called the higher order function

　　　　　　

 def  fun_3 (fun): #  fun_3 is a higher-order function  print  ("  3   " )  return   fun  def   Fun_4 ():  print  ("  4   " )  #  fun_3 (fun_4) () #返回值可以直接运行  fun=fun_3 (fun_4) #   You can assign the return value to a variable  Fun () #   can call function  

Nested functions:

Define a new function in the function called a nested function

　　　　

1 def fun_5 ():#fun_5 for nested functions 2     print('5' )3     def  Fun_5_1 ():4         print('  5.1')5     6 fun_5 ()

The simplest of decorations:

1 defFun_2 (Fun):#functions passed into fun_12     deffunction ():3     4 Fun ()5         Print('In the fun_2 ...')#Add new Content6     7     returnfunction8 9@fun_2#Decorative fun_! Equivalent to Fun_1=fun_2 (fun_1)Ten deffun_1 (): One     Print("In the fun_1 ....") A  -  -Fun_1 ()

Decorator: Analogue Login Certification

1 #Analog Website Login access authentication2 #3Name='ABC'4password='123'5 defCerti (model):#Decorative Device6     defOutr (Fun):#Adorner plus parameter requires extra nesting7         defLogin (*args,**kwargs):#to be compatible with various function parameters, add *args,**kwargs invariant parameters8             ifmodel=='Password':9                 Print('This is password certification .')Tenuser_name = input ('User name:'). Strip () OnePaswd=input ('Password:'). Strip () A                 ifUser_name==name andpaswd==Password: -                     Print('through Certification') -                     returnFun (*args,**Kwargs) the                 Else: -                     Print('user or password error, exit') - exit () -             elifmodel=='Lamp': +                 Print('This is the lamp certification') -                 returnFun (*args,**Kwargs) +             Else: A                 Print('Authentication Error') at         returnLogin -     returnOutr -  -  - defindxe (): -     Print('Welcome to Homepage') in  -@certi (model='Password') to defUser (): +     Print('Welcome to the user page:') -  the@certi (model='Lamp') * defBBS (name): $     Print('Welcome to%s Landing Forum !'%name)Panax Notoginseng  - Indxe () the User () +BBS (name='YJJ')

　　

Python 11th day